/*
 * @author 707<707472783@qq.com>
 * This program is for checking the value.
 */
#include <iostream>
int main()
{
    unsigned u = 10, u2 = 42;
    std::cout << u2 - u << std::endl;
    std::cout << u - u2 << std::endl;
    
    int i = 10, i2 = 42;
    std::cout << i2 - i << std::endl;
    std::cout << i - i2 << std::endl;
    std::cout << i - u << std::endl;
    std::cout << u - i << std::endl;
    return 0;
}
